Levels of pesticide residues during and after pomegranate peel powder production

In this study, the effects of sun and oven drying processes used in the production of pomegranate peel powder, a valuable waste product of the food industry, and subsequent non-thermal processes (gamma irradiation, UV-C, and ozone gas) on the pesticides present in pomegranate peel were investigated. Additionally, the effects of the these drying processes and subsequent non-thermal processes on the color values, antioxidant (AO) activity value, and total phenolic content (TPC) of pomegranate peel were investigated. It was determined that both drying processes resulted in decreases in pesticide levels and that sun drying caused greater pesticide degradation than oven drying. However, among the pesticides studied, only azoxystrobin level in sun-dried samples was found to be statistically lower than in oven-dried samples (P<0.05). Among the pesticides examined, acetamiprid, which had the lowest octanol/water partition coefficient, and pyriproxyfen, which had the highest vapor pressure, showed the greatest reductions. The drying processes applied did not cause a statistically significant difference in the a* value of the pomegranate peel, while sun drying caused statistically significant differences in the L* value and oven drying caused statistically significant differences in both the L* and b* values. AO activity value decreased by 12% and 16% as a result of sun drying and oven drying, respectively. Sun drying resulted in a 16% decrease in TPC, while oven drying resulted in a decrease of 15%. After drying, 10 kGy gamma irradiation treatment applied to pomegranate peel powder samples caused a limited pesticide degradation (maximum 12%). UV-C (20.71-82.86 J/cm2) and ozone (0.59%; v/v) treatments were performed for 2-8 hours. In both treatments, pesticide degradation increased as the treatment time increased. The pesticides studied degraded by 11-72% as a result of UV-C treatment and by 18-85% as a result of ozone treatment. Acetamiprid was the least degraded active ingredient due to its lower content of functional groups and unsaturated bonds compared to other active ingredients. It was determined that statistically significant decreases (P<0.05) in the TPC and AO activity of the samples occurred when UV-C and ozonation treatments were applied for long periods. It was observed that the drying processes applied to pomegranate peel and the subsequent non-thermal processes were effective on the studied pesticides and some quality parameters of the product.